Below is a transcription of this video, which was created by the Hager Companies.
This pre-installation video will cover the parallel arm mounting of the 5100 regular door closer and the heavy-duty arm combinations used with the 5100.
First, unbox your 5100 regular door closer. If you are installing the closer in a parallel arm installation, seen here on the instruction sheet, this video is for you. If you have a heavy-duty version of the 5100, go ahead and unbox the door closer. On the top of the instruction sheet, you will see the different heavy-duty arm types available with the 5100. All heavy-duty arms are installed in their parallel arm configuration. Remove the two hex wrenches from the screw packs. The larger one will be used for the spring adjustment, and the smaller one for the valve adjustments.
For all 5100 installations in a parallel arm configuration, the back check selector valve must be turned in completely. The back check selector valve is located on the backside of the closer body. Turn the body over to locate the valve, and using the smaller wrench, rotate the back check selector valve clockwise until it is all the way in. The spring power can be adjusted using the larger hex wrench to turn the screw at the end of the closer body.
The 5100 door closer is shipped from the factory at size 3. Consult the instruction sheet to determine whether you need to decrease the spring size or increase the spring size depending on the width of your exterior or interior door. The chart will indicate how many turns need to be made, either clockwise to increase the power or counterclockwise to decrease it. You have made the initial adjustments and are ready to install your door closer.